-LRB- CNN -RRB- -- The White House confirms that Syria has crossed a `` red line '' by using chemical weapons in its war with rebel forces , prompting the United States to boost the `` scale and scope '' of its support for the opposition .

The determination , disputed by Syria , comes as forces loyal to Syrian President Bashar al-Assad have made gains in the past few weeks . Also , the militant group Hezbollah has become more active in the fighting on behalf of the regime .

The opposition has warned it could face crippling losses without immediate support .

What 's next ?

The Obama administration was resisting calls to arm the rebels , worried in part about the influence of radical groups and that weaponry might wind up in the wrong hands .

But it has now changed course .

It is going to provide military support including small arms , ammunition and potentially anti-tank weapons to the rebels , according to two officials familiar with the matter . The weapons will be provided by the CIA , the officials said .

The White House said earlier said no decision had been made on whether to impose a `` no-fly '' zone . That is something rebels have said is needed to halt air attacks on their strongholds .

The United States has also ruled out sending troops , or putting `` boots on the ground '' in Syria .

What 's been the U.S. response ?

The Obama administration had previously authorized non-lethal assistance , including communications equipment , medical supplies and food . The first direct U.S. support arrived in March .

Obama signed off on a new package of non-lethal aid April . That assistance was expected to include body armor , night-vision goggles and other military equipment .

Defense Secretary Chuck Hagel also ordered the deployment of up to 200 additional U.S. troops to Jordan in April as the violence spreads from adjacent Syria .

Those forces included communications and intelligence specialists aimed at assisting the Jordanians and `` be ready for military action '' if Obama were to order it , a Defense Department official said .

A number of U.S. special forces troops have been in Jordan for the past year assisting that nation 's the Jordanians .

Jordan is a crucial U.S. ally in the Middle East and has experienced an influx of hundreds of thousands of refugees from the fighting in Syria .

The United States is also deploying a Patriot anti-missile battery and F-16 aircraft to Jordan as part of military exercises taking place this month .

It is not clear whether any of those assets will remain in Jordan once the regional exercises are complete . The Syrians possess Scud missiles .

The United States also has deployed Patriot missiles to Turkey , which also borders Syria . Officials say those missiles are defensive in nature . Syria employs SCUD rockets .

Would NATO join the U.S. ?

Questions still remain about whether NATO would assist the U.S. militarily , similar to its help in enforcing a `` no-fly '' zone over Libya during that country 's period of civil unrest .

In the past , NATO has flatly ruled out military intervention and the United States has no plans to put boots on the ground .

But on Friday , NATO Secretary General Anders Fogh Rasmussen said the international community had made clear that any use of chemical weapons is `` completely unacceptable and a clear breach of international law . ''

Speaking in Brussels , he said he welcomed `` the clear U.S. statement '' on Syria 's alleged chemical weapons use and that it was a matter of great concern .

`` As for NATO , the Patriot deployment will ensure effective protection for Turkey against any missile attack , whether the missiles carry chemical weapons or not , '' he said .

Additional military options ?

â $ cents Targeting Syria 's air defenses with Patriot missile batteries in Turkey as part of a `` no-fly '' response , NATO has said . But Turkey only allowed the missiles there for defensive purposes and NATO nations would have to agree before they could be used otherwise .

â $ cents Airstrikes : The U.S. military has enough air power in the region to take action against Syria , according to officials . That includes fighter jets and bombers spread out across air bases in the Middle East and nearby aircraft carriers . The Navy also has warships equipped with Tomahawk missiles , which could be used to hit chemical weapons supplies .

But such strikes pose a danger of releasing chemical agents into the air around civilian populations in Syria , U.S. officials told CNN in March .

Complicating military involvement

What complicates any U.S. military support for the opposition is that many of the rebel fighters are militants with pro-al Qaeda sympathies , the same stripe of militants America has battled in Iraq and Afghanistan .

In April , Hagel cautioned lawmakers on the Senate Armed Services Committee about the difficulties surrounding any direct U.S. military action in Syria .

`` It could embroil the United States in a significant , lengthy and uncertain military commitment , '' he said .

He called military intervention `` an option but an option of last resort . ''

Joint Chiefs Chairman Gen. Martin Dempsey said the United States could send troops to Syria if al-Assad 's government fell , if needed , to secure chemical weapons .

CNN 's Jessica Yellin , Barbara Starr , Chris Lawrence , Tom Cohen and Elise Labott contributed to this report .

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NEW : U.S. through CIA to provide small arms , ammunition , sources say

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Opposition warns it could face crippling losses without support now

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NEW : No American `` boots on the ground '' ; No word on any `` no-fly '' option

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Rebel fighters include militants with pro-al Qaeda sympathies